Single-Leg Bridge on Stability Ball

Lie on the floor with your heels up on a ball and your hips lifted so your body forms a straight line. Lift your right leg toward the ceiling as far as possible. Slowly lower your leg and gently place your heel on the ball. Repeat with the left leg, and keep alternating for a full set. Start with one set of five reps on each leg, and progress to two sets of 10 each. If stability is a problem, start by keeping both legs on the ball and simply raising and lowering your hips for 10 reps.